. >> reporter: the snow didn't keep the philadelphia eagles or the detroit lions off the field but the powerful winter storm that's been moving across the country has been wreaking havoc on roads and airports where thousands of flights have been canceled or delayed. the dangerous mix of freezing rain, sleet and snow blanketed the southwest and then pushed north and east. it's expected to leave up to a foot of snow in pennsylvania where a multicar pileup left one person dead. car crashes in other states took at least six more lives. >> it's almost like a one-two punch. there's cold air to the north, warm air to the south and it creates a very dangerous mixing line of ice and rain. the mix is almost more dangerous than straight snow. >> reporter: the wintry mix has hit new york where the snow is expected to turn to rain before the temperatures go back up into the high 40s. the vast storm left icy texas highways almost abandoned. >> seemed like there's ice, snow and ice again. >> reporter: it also stranded thousands of the dallas fort worth airport and briefly grounded planes in philadelp